Electrolytic cells for the electrolysis of alkaline salts.



M. WILDERMANN. ELECTROLYTIC CELLS FOR THE ELBOTROLYSIS 0P ALKALINESALTS.

APPLICATION IILED DEO.10, 1910. 998,Q63 Patented July 18, 1911.

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. I APPLICATION FILED DEO.10, 1910. 99 0 3 v v Patented July 18,1911.

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MEYER WILDERMANN, OF EALING, LONDON, ENGLAND.

ELECTROLYTIC CELLS FOR THE ELECTROLYSIS OF ALKALINE SALTS.

Specification of Letters Patent.

Iatented July 18, 1911.

Application filed December 10, 1910. Serial No. 596,682.

To all whom it may concern:

Be it known that I, MEYER VVILDERMANN,

chemist, a subject of the Czar of Russia,

and resident of 10 Elers road, Ealing, Lon don, Vii, England, haveinvented certain new and useful Improvements in Electrolytic Cells forthe Electrolysis of Alkaline Salts, of which the following is aspecification. I

In Letters Patent No. 741864 an electrolytic cell with stagnant orstationary mercury cathode has been described, in which the mercury iscontained in superimposed troughs. Within the troughs carbons float onthe caustic side. Now it has been experienced that if these troughs areworked with high current densities, so that a great gas developmenttakes place in the trough,

and especially if, in consequence of the em ployment of manysuperimposed troughs, a gas current is set up on the alkaline hydrateside, the little carbons in the troughs are oved too far away from themercury, and e even thrown out, and that in conse quence of this it mayeven happen that the process cannot be carried out any further. On theother hand, the surface of the mercury rises and falls in accordancewith the unavoidable alterations in the specific gravities of thesolutions at the chlorin-, and the alkaline hydrate side. The littlecarbons, therefore, must also beable to freely move up and down, so asto remain onjthe mercury. In practical working a free space of about 2-3mm. is sufficient for this move-f ment. According to the invention,arrangements, examples of which are shown in the drawing, are used forthis purpose.

Figure 1 represents a longitudinal section through a circular cell.

Fig. 2 is a plan view of a rectangular cell.

In order to prevent'the falling out of the little carbons for instancebars I) provided with suitable teetha are employed, as shown in Fig. 1on the left hand side, or the troughs c themselves are provided atsuitable intervalswith small noses d, as shown in Fig. 1 on the righthand side, so as to keep the little carbons e in their positions.Especially in circular cells also perforated carbons can be drawn upon awire, and they can then be kept in their positions, by a suf-' ficientnumber of toothed bars or by projections on the troughs. Perforated ornonperforated carbons can, for the samepurpose, also be fastened --tosmall weights, which would keep them in position, the little weightsbeing covered with ebonite. The

little carbons themselves are wound with ,7

wire, as is wellknown, in order to produce electrical contact with themercury.

In electrolytic cells of the type described it is further essential thatthe mixing action of the stirrers upon the amalgam only takes place atthe chlorin side and that the amalgam, which is only mixed at thechlorin sideis not mechanically transported from the decomposing chamberinto the combining chamber by a movement imparted by the stirringblades. The amal-, gain, on the contrary, shall be transported frombeneath the rib of the trough to the surface of the mercury on the NaOHside, in consequence of its buoyancy. With this working of the stirrers,which relates to the bodily transmission of the amalgam from the chlorinside to the NaOH side, and which assumes a sufiicient mixing action formixing the amalgam on the chlorin side as homogeneously as possible, onepoint however, has not been sufficiently taken into consideration. Theamalgam, namely, must not only not be bodily moved from the chlorin sideto the NaOH side, but th mercury must not be moved on the NaOH sidealong the trough or the formation of waves will result. in the same,especially along the rib providing the seal, and to insure the cellhaving on the NaOH side along the. rib

practically a stagnant cathode, whereas the movement of the cathode onthe chlorin side is unavoidable. The above'is necessary liquid from onecompartment to the other in consequence of the small seal on the rib,

thereby to avoid the NaOH being impurified by salt and especially thepassage of the alkaline hydrate solution to the chlorin side and theformation of hypochlorites,

which would destroy the anodes, and to prevent the decreased etficiencyconnected ing of the amalgam with a movement of the mercury asrestricted as possible is attainable. If, for instance, the number ofthe stirring arms 7 is doubled, then the stirrer g has in the same timeto pass only half thedistance, and in consequence of this the stirringarms f pass the amalgam just as often as before and mix the amalgam inthe same way as before however, they only move the same half thedistance. The impact of the stirrers against the mercury and theprogressive movement of the latter caused thereby is considerablylessened in this mannor, the progressive 'n'iovement of the mercurybeing further lessened at smaller distances when reversing the movementof the stirrers, by the. surfaces of the stirrers themselves. In thesame manner small ribs it can be arranged in suitable distances withinthe trough at the chlorin side or at the chlorinand the alkaline hydrateside, in order to prevent the progressive movement of the mercury. Inthe same mannersmall ribs can be employed at the bottom of the troughinstead of above on the chlorin side alone or on the chlorin and causticside, or toothed bars can be employed at suitable distances on thechlorin or chlorinand caustic side. In every case, however, the numberof the stirrers and of the divisions in the troughs has to be chosen insuch a manner that with a sufficient mixing of the amalgam necessary fora high efiiciency the mercury at the alkaline hydrate side practicallydoes not show .any wave movement at the lower rib of the trough, but hasa smooth surface.

What I claim as new and desire to secure by Letters Patent is 1.- Inelectrolytic cells for the electrolysis of alkaline salts provided witha mercury cathode contained in superimposed troughs, with division ribsdipping into the mercury, with stirrers for mixing the mercury andamalgam on the anode side, with carbons floating on the mercury on thecathode side the provision of means for preventing the carbons from.rising over a certain height in the troughs.

2. In electrolytic cells for the electrolysis of alkaline salts providedwith a mercury cathode, contained in superimposed troughs, with divisionribs dipping into the mercury,

of the trough.

with stirrers for mixing the mercury and amalgam on the anode side, with'carbons on the mercury on the cathode side, the provision of means forpreventing wave movements of the mercury on the cathode side along thetrough at the lower rib.

In electrolytic cells for the electrolysis of alkaline salts providedwith a mercury cathode, contained in superimposed troughs, with divisionribs dipping into the mercury, with stirrers for mixing the mercury andamalgam on the anode side, with carbons on the mercury on the cathodeside, limiting supports for preventing the carbons from rising over acertain height in the troughs and means for preventing wave movements ofthe mercury on the cathode side along the trough.

4. In electrolytic cells for the electrolysis of alkaline salts providedwith a mercury cathode, contained in superimposed troughs with divisionribs dipping into the mercury. with stirrrersfor mixing the mercury andamalgam on the anode side, with carbons on the mercury on the cathodeside, the provision of small weights for preventing the carbons fromrising over a certain height in the troughs, and of means for preventingwave movements in the mercury on the oathode side along the trough atthe lower rib 5. In electrolytic cells for the electrolysis of alkalinesalts provided with a mercury cathode, contained in superimposed troughswith division ribs dipping into the mercury, with stirrers on the anodeside for mixing the mercury. with carbons placed on the mercury on thecathode side, the provision of means for preventing the carbons fromrising over a certain height in the trough, and means for preventing themercury on the cathode side from receiving wave movements along thetrough. said means comprising surfaces limiting the movements of themercury within the troughs.

6. In electrolytic cells for the electrolysis of alkaline salts providedwith a mercury cathode, contained in superimposed troughs withdivision-ribs dipping into the mercury, with stirrers on the anode sidefor mixing the mercury, with carbons placed on the mercury on thecathode side, the provision of means for preventing the carbons fromrising over a certain height in the trough, and means for preventing themercury on the cathode side from receiving wave movements along thetrough, said means comprising projections in the troughs.

7. Inelectrolytic cells for the electrolysis of alkaline salts providedwith a mercury cathode, contained in superimposed troughs with divisionribs dipping into the mercury, with stirrers on the chlorin side formixing the mercury, with carbons placed on the mercury on the causticalkali side, the provision of means for preventing the carbons Intestimony whereof, I afiix my signature from rising over a certainheight in the in presence of two witnesses. trough, and means forpreventing the mer- E T N. cury on the CBJJ StIC SIdG from receivingwave M WILDERMAN movements along the trough, said means Witnesses:consisting in choosing the number of stlrrers FRIEDRICH EDELMANN, thatno Wave movement W111 result. JULIUS OPPENHEIMER.

